Enhancing Tomotherapy for Brain Tumors: A Noncoplanar Technique with Improved Dosimetric Outcomes

Background: Tomotherapy, as a radiotherapy technique, is limited by its inability to deliver noncoplanar beams, which are often critical for isodose conformity. Objectives: The presnt study introduces a head base plate that allows pitch and yaw adjustments to facilitate noncoplanar radiation delivery with improved dosimetric outcomes. Methods: A custom-designed head base plate was developed and integrated into a standard tomotherapy system to allow controlled noncoplanar beam delivery. A phantom study was conducted to compare dosimetric outcomes between coplanar and noncoplanar techniques for a pseudo-hypophysis tumor. Key dosimetric parameters, including dose distribution and dose-volume metrics for target and organs at risk (OARs), were evaluated. Results: Noncoplanar tomotherapy demonstrated improved dose conformity and homogeneity, with a superior dose-volume ratio (90% - 110%) compared to the coplanar approach. Significant reductions in OARs doses were observed, particularly in the eyes and optic nerves, ranging from 2.2 to 3.9 Gy. These enhancements were achieved without compromising target coverage or increasing low-dose spread. Conclusions: The noncoplanar technique, facilitated by the proposed head base plate, offers significant dosimetric benefits, enhancing the safety and efficacy of tomotherapy for brain tumors. This innovation addresses a key limitation of tomotherapy systems and holds potential for broader clinical applications.